The FDA is approving Orlistat - a new drug which interferes with the body’s ability to absorb fat. This results in a de facto reduction in dietary fat. According to advanced billing, it promises to reduce absorption of about 1/3 of the fat in a given meal by blocking lipase. So a 30% fat diet would become in effect, a 20% fat diet. This results in a de facto 10% reduction in calorie density so it is likely that it will produce a modest weight loss. Of course it will also cause a modest amount of fat in the stool and the physiological consequences of all this extra fat in the colon may not be harmless. Orlistat will reduce the absorption of fat soluble vitamins and fat soluble phytochemicals which is a cause for concern. Because SFA and cholesterolabsorption will be reduced, Orlistatwill reduce serum cholesterol modestly in most people.Olean, now found in some fat free salty snacks, is similar nutritionally to mineral oil. It can cause digestive problems if consumed in quantity. Wow Potato Chips, made with Olean, have half the caloric density of regular potato chips but at 1200 calories per pound, they are still calorie-dense. Like Orlistat, they will aid weight loss if substituted for fatty chips (2300 to 2750 calories per pound) but I do not see them as being of much practical value for weight loss. There is concern about the major loss of carotenoids in the stool of people consuming even modest amounts of sucrose polyester. This loss of carotenoids could increase the risk of cancer and heart disease.The best of the bunch of new fat substitutes and fat blockers will likely be Nu-Trim, which is made from beta-glucan, the soluble fiber in oats. Nu-Trim can replace up to 75% of the fat in muffins and ice cream without significant changes in taste or texture. As a soluble fiber, it will probably improve colon function as most people eat too little fiber. It will lower cholesterol by allowing the reduction of milk fat in ice cream and trans fatty acids in muffins; additionally, its soluble fiber will lower cholesterol and insulin response when added to the diet. Unlike Orlistat and Olean, it will not lead to significant nutrient and phytochemical losses. Perhaps its only drawback is that it cannot be used to fry foods the way Olean can.By Dr. Jay Kenney, PhD, RD, FACN.